Search Results (1,103)

Background/Objectives: The widespread use of sulfamethoxazole (SMX) has led to increasing antibiotic resistance, and there is a need for improved formulations to enhance its therapeutic effectiveness. In this study, we investigated the biocidal potential of SMX composite crystals incorporated with functionalized poly(lactic-co-glycolic acid) (nfPLGA) and nano-graphene oxide (nGO). Methods: The composites, namely SMX-nfPLGA and SMX-nGO, were synthesized via antisolvent precipitation and evaluated using Kirby–Bauer disk diffusion assays. Results: Incorporation of nfPLGA and nGO significantly improved SMX solubility, increasing it from 0.029 mg/mL to 0.058 mg/mL and 0.063 mg/mL, respectively. Additionally, the log partition coefficient (log P or K_w) also improved from 1.4 to 0.86 for nGO and 0.92 for nfPLGA composites. Both formulations exhibited improved antibacterial activity with distinct time-dependent bactericidal effects. Compared to pure SMX, the SMX-nfPLGA showed 60% and 53% greater bacterial inhibition at concentrations of 50 mg/mL and 100 mg/mL, respectively. Although SMX-nGO was slightly less potent, it still surpassed pure SMX, with 50% and 33% higher inhibition at the same concentrations. Conclusions: Importantly, neither nfPLGA nor nGO showed any biocidal effects, confirming that the observed enhancement was due to improved SMX solubility caused by their incorporation. These findings suggest that embedding solubility-enhancing nanoparticles into the existing crystal structure of the antibiotic is a promising strategy for enhancing the effectiveness. Full article

According to existing ecological problems, one of the promising developments is the creation of polyfunctional materials, which can be biodegradable, along with possessing antibacterial activity. The present research proposes biocomposites based on PLA with silver nanoparticles (AgNPs) and natural polysaccharides obtained in a twin-screw extruder. Introduction of polysaccharides to PLA-based biocomposites with/without AgNPs led to significant decrease in the elastic modulus and tensile strength, while the elongation at break remained almost unchanged. Thanks to the presence of natural polysaccharides, there was intensified biodegradation in soil despite the AgNP availability. The maximal mass loss was 29% for the PLA–PEG₁₀₀₀–starch + AgNPs (80:10:10 + 0.5 wt%) biocomposite. Analyses of the systems before and after soil exposure were carried out using DSC and FTIR spectroscopy methods. According to a thermal analysis, it was found that PLA crystalline regions degrade during exposure to soil. The same feature was detected during the spectral analysis. The intensity of the characteristic absorption bands of PLA decreased. Furthermore, it was found that the dark areas on the surface of the materials are of a polysaccharide nature and may be signs of biofouling of the materials by microbial flora. The tests on fungus resistance showed that biocidal additives such as AgNPs in PLA-based biocomposites with polysaccharides did not inhibit the development of mycelial fungi–biodestructors. And the increased amount of chitosan in the films contributed to their more active destruction by the end of the observation period. It was demonstrated that such biocomposites can inhibit bacterial growth. Full article

Metal-free aminobenzoic acid-derived Schiff bases are attractive antimicrobial leads because their azomethine (–C=N–) functionality enables tunable electronic properties and target engagement. We investigated whether halogenation on the phenolic ring would modulate the redox behavior and enhance antibacterial potency, and hypothesized that heavier halogens would favorably tune physicochemical and electronic descriptors. We synthesized three derivatives (SB-3/Cl, SB-4/Br, and SB-5/I) and confirmed their structures using FTIR, ¹H- and ¹³C-NMR, UV-Vis, and HRMS. For SB-5, single-crystal X-ray diffraction and Hirshfeld analysis verified the intramolecular O–H⋯N hydrogen bond and key packing contacts. Cyclic voltammetry revealed an irreversible oxidation (aminobenzoic ring) and, for the halogenated series, a reversible reduction associated with the imine; peak positions and reversibility trends are consistent with halogen electronic effects and DFT-based MEP/LHS descriptors. Antimicrobial testing showed that SB-5 was selectively potent against Gram-positive aerobes, with low-to-mid micromolar MICs across the panel. Among anaerobes, activity was more substantial: Clostridioides difficile was inhibited at 0.1 µM, and SB-3/SB-5 reduced its sporulation at sub-MICs, while Blautia coccoides was highly susceptible (MIC 0.01 µM). No activity was detected against Gram-negative bacteria at the tested concentrations. In the fungal assay, Botrytis cinerea displayed only a transient fungistatic response without complete growth inhibition. In mammalian cells (HeLa), the compounds displayed clear concentration-dependent behavior. Overall, halogenation, particularly iodination, emerges as a powerful tool to couple redox tuning with selective Gram-positive activity and a favorable cellular tolerance window, nominating SB-5 as a promising scaffold for further antimicrobial optimization. Full article

Biodeterioration represents a major threat to cultural heritage, as microbial colonization can cause both esthetic and structural damage. The use of conventional chemical biocides raises concerns due to environmental and health risks, potential substrate deterioration, and the emergence of resistant strains. In this study, an ozone-loaded bacterial cellulose (OBC) hydrogel was investigated as an eco-friendly, broad-spectrum antimicrobial treatment in the case study of the Cryptoporticus of the Baths of Trajan (Rome, Italy), a hypogean archeological site where some structures are severely affected by phototrophic biofilms. Microorganisms isolated from a colonized wall were employed in laboratory assays. OBC hydrogel exhibited strong antimicrobial activity, with >90% bacterial mortality within 10 min, complete inhibition of fungal spore germination after 24 h, and a marked reduction in microalgal chlorophyll fluorescence comparable to heat-killed controls. Furthermore, tests on Carrara marble and brick specimens artificially contaminated with microalgae confirmed the removal of green staining, restoring surface chromatic parameters (ΔE* < 5) comparable to those obtained with a commercial biocide. In situ applications demonstrated significant suppression of green biofilm for at least two months. These findings support OBC hydrogel as a sustainable, effective, and non-toxic alternative to conventional biocides for controlling microbial and microalgal colonization on cultural heritage surfaces. Full article

The two-spotted spider mite, Tetranychus urticae, is a global pest with increasing resistance to conventional acaricides, prompting the search for sustainable alternatives. Essential oils (EOs) are promising botanical biocides due to ecological safety and multitarget action. We evaluated lethal and sublethal effects of EOs from Alpinia zerumbet and Mesosphaerum suaveolens against T. urticae. Oils were obtained by hydrodistillation and characterized by GC–MS (major constituents: A. zerumbet—1,8-cineole 14.05%, sabinene 12.6%; M. suaveolens—β-sabinene (predominant), spathulenol 12.28%, 1,8-cineole 11.01%). In adult bioassays, M. suaveolens was more toxic (LC₅₀ = 4.24 µL mL⁻¹), whereas A. zerumbet showed LC₅₀ = 8.74 and LC₉₀ = 46.24 µL mL⁻¹. In ovicidal assays at LC₉₀, egg viability declined to 2% with A. zerumbet versus 57% with M. suaveolens. Repellency at sublethal concentrations (LC₂₀–LC₃₀) was high for both oils (≥75%) and exceeded 90% for M. suaveolens. Both oils suppressed population growth (instantaneous rate r_i reduced from 0.5848 in the control to 0.4746–0.5155 under treatments). PCA confirmed lethal concentration and repellency as the main discriminators among treatments. These data demonstrate the multitarget potential of A. zerumbet and M. suaveolens EOs as botanical acaricides for sustainable management of T. urticae. Full article

Shipboard ballast water management systems (BWMS) commonly employ chlorine or other oxidants to treat ballast. Oxidant-based BWMS inject these biocides to meet a concentration threshold or target value that is lethal to most aquatic organisms. Resulting concentrations of total residual oxidant (TRO) may span two orders of magnitude between initial doses (e.g., ~10 mg L⁻¹) and discharged ballast, which must meet discharge limits (e.g., <0.1 mg L⁻¹). Here, we evaluated three TRO instruments (two colorimetric-based and one based on amperometry) that have been integrated into BWMS for use in shipboard applications. Our study quantified accuracy and precision using test waters along a range of temperatures and salinities, using a pipe loop to mimic in-line shipboard operations, where the instruments continuously sample and analyze circulating water. Linear regression analysis compared the instruments to a standard reference method along a range of concentrations relevant to oxidant-based BWMS. In general, measurements from the TRO sensors showed strong linear relationships to the reference method, but slopes of these relationships were significantly <1 in all but one instance. Precision—measured as the coefficient of variation—ranged from 2 to 4%. These initial tests occurred on units shipped directly from the manufacturer, immediately following calibration and quality checks, and in a controlled laboratory environment. Thus, in this context, our evaluations represent a “best-case” outcome. We recommend that laboratory studies (as described here) be paired with endurance trials and in-service monitoring to include tests in a shipboard environment. These trials should evaluate TRO instruments that are integrated with BWMS and functioning under normal ship operations, measuring both high (treated ballast) and low (neutralized discharge) concentrations of TRO. Shipboard trials in concert with frequent calibration checks will reduce the risks of under- or overestimating TRO concentrations, as both outcomes may harm the environment. Full article

Hybrid hydrophobic coatings (HHCs), which combine organic and inorganic materials, have demonstrated superior weathering resistance compared to conventional organic coatings in conserving stone heritage structures. Among the inorganic components of HHCs, nanosilica is especially promising because of its ability to form durable, weathering-resistant and hydrophobic silane-based structures. This overview examined recent studies, advances, and emerging trends about nanosilica-based HHCs from 2020 to 2024 using the “Boolean strategy” and search terms “stone”, “heritage”, “hydrophobic”, and “coating”, capturing 5244 articles. After screening for titles containing “nanosilica” (470 items remained), excluding works related to “consolidants” and “cement” (171 items remained), and requiring quantitative data on formulations, methods, and performance of nanosilica-based HHCs in stone heritage structures, 16 relevant works were identified. China and Italy dominated research works on nanosilica-based HHC development, which was applied to stone heritage structures composed of carbonate materials (e.g., limestone, dolomite, and Palazzolo carbonates) and silica-rich materials (e.g., Qingshi stone, Hedishi stone, and red sandstone). Key evaluation metrics reported by multiple authors to evaluate HHC efficacy included water contact angle (WCA), total color difference (TCD), and solution pH. Moreover, ultraviolet light (UV) durability, thermomechanical stability, biocidal efficiency, and graffiti protection were achieved when nanosilica was combined with other nanomaterials. Integrating emerging technologies, such as artificial intelligence (AI), internet-of-things (IoT), and smartphones with colorimeter apps could improve accessibility, real-time monitoring and reliability of HHC testing, while adherence to standardized testing protocols would further enhance comparability and practical application across studies. Overall, this overview provides valuable insights into nanosilica-based HHCs for researchers and restorers/conservators of stone heritage structures. Full article

The propagation of antibiotic resistance genes (ARGs) in aquatic environments poses a significant threat to global health. This study compared sediment resistome profiles in river crab (Eriocheir sinensis) polyculture systems with and without stone moroko (Pseudorasbora parva). The results showed that, compared to the control group (MC group), the sediment from the polyculture system containing stone moroko (PC group) exhibited significant reductions in the total abundances of ARGs, metal resistance genes (MRGs), biocide resistance genes (BRGs), and mobile genetic elements (MGEs). Crucially, the total abundance and composition of MGEs in pond sediment were substantially correlated with ARGs, MRGs, and BRGs, respectively. Co-occurrence network analysis revealed that there was only one edge between ARGs and MGEs in the PC group, whereas the MC group had eight edges. Additionally, the proportion of mobile ARGs in the PC group was significantly lower than that in the MC group. Alterations in resistome profiles were markedly associated with decreased levels of total carbon (TC) and phosphate in the sediment. All of the findings demonstrated that the introduction of stone moroko in the river crab polyculture system effectively mitigated the sediment resistome primarily by altering environmental factors and suppressing MGEs, thereby disrupting the horizontal transfer network of resistance genes. This study highlights the potential of leveraging aquatic biota as a novel biological strategy for the in situ management of environmental antimicrobial resistance. Full article

Biofouling by mussels is responsible for serious economic losses worldwide. In Argentina, Limnoperna fortunei (Dunker, 1857) and Brachidontes rodriguezii (d’Orbigny, 1842) are common and abundant bivalve species of great interest, inhabiting freshwater and marine coasts, respectively. Both species are considered fouling pests for coastal industrial facilities that use untreated water as part of their processes. To chemically control mussel biofouling, it is necessary to find efficient and environmentally friendly non-biocidal compounds. In this work, we report the antifouling activity of three phenolic compounds (hydroquinone, resorcinol, and catechol) and their respective acetylated derivatives against L. fortunei and B. rodriguezii mussels. Classic ecotoxicity tests with Artemia salina were also performed. Acetylated phenolic compounds were synthesized in the laboratory by sustainable chemistry procedures. Results revealed the importance of hydroquinone, resorcinol, and catechol and their diacetylated derivatives for preventing the settlement of both these mussels, in a non-biocide way. Ecotoxicity bioassays revealed that these compounds were not toxic, with the exception of resorcinol. We propose the incorporation of these compounds in solution into closed circuits and water sprinkler anti-fire systems to prevent the settlement of L. fortunei and their inclusion in antifouling paints to prevent the settlement of B. rodriguezii. These results highlight a new friendly alternative for controlling mussels. Full article

Chemical disinfection of removable acrylic dental prostheses minimizes the risk of denture stomatitis caused by the opportunistic fungal pathogen Candida albicans. We previously reported that neutral-pH electrolysed oxidising water (EOW), a hypochlorous acid (HOCl)-based biocide, is effective at inhibiting C. albicans biofilm formation on denture resins. Knowledge about the mechanism of action of EOW on C. albicans is lacking. This study investigated the molecular mechanism of action of neutral-pH EOW against C. albicans cells that were incubated with sub-inhibitory concentrations of EOW-HOCl (treatment with 0.125× MIC₉₀ EOW-HOCl (15 µM; T0.125) or treatment with 0.5× MIC₉₀ EOW-HOCl (59 µM; T0.5)). RNA-sequencing (RNA-seq) was used to identify differentially expressed genes (DEGs) which were validated by qRT-PCR. Ninety-five DEGs were identified between the treated and untreated cells after a 60 min exposure. A moderate sub-inhibitory EOW-HOCl concentration (T0.125) caused significant upregulation (log₂ fold change > +2) of genes responsive to oxidative stress (EBP1, GAP6, PRN1, HSP21), weak organic acid stress (PRN1), and heat-shock (HSP21). A higher sub-inhibitory concentration (T0.5) caused a significant downregulation of most DEGs (notably, −1.9 to −3 log₂ fold reduction in SUT1, HNM3, STP4 expression), cessation of growth, and an upregulation of genes involved in ammonia transport, carbohydrate metabolism, and the unfolded protein and apoptotic response pathways (ATO2, IRE1). Our findings reveal HSP21 and PRN1 to be possible key players in protecting C. albicans cells against HOCl, a natural biocide of the innate immune system. Full article

The aim of this study was to find a way to remove persistent bacteria inhabiting in vitro shoot cultures of raspberry. Often, decontamination treatments fail to reach bacteria residing in internal tissues, leading to contaminated cultures later. Three raspberry cultivars, each harboring a unique bacterial contaminant, were used in this study. Experiments were conducted to assess the potential for eliminating these bacteria using biocide infiltration at 30 mbar. The following biocides were used: mercuric chloride (HgCl₂ at 0.05 and 0.1%), Plant Preservative Mixture (PPM^TM 0.2–4%), rifampicin (50–200 mg L⁻¹), and sodium hypochlorite (NaOCl 0.1–60%). Only 0.05 or 0.1% HgCl₂ applied via infiltration successfully eliminated all of the bacteria from the shoots, which remained bacteria-free for several years, as confirmed by indexing explants on bacterial media at each subculture. While most treated shoots became necrotic and died due to infiltration, the surviving shoots remained vital and provided bacteria-free material for long-term propagation. Results from experiments comparing micropropagation potential in bacteria-contaminated and bacteria-free cultures showed that bacteria-free shoots produced longer shoots, and the total number of shoots did not differ, except for ‘Norna’/Curtobacbacteria-free cultures, which were more productive. Bacteria-contaminated shoots rooted at higher percentages, but roots were much shorter, and plantlets initiated growth during acclimatization later. Cultures that were contaminated did not survive storage at 4 °C in the dark for 4–6 months. Full article

This research explores the potential introduction of marine waste-derived biological fillers within bio-epoxy matrices to mitigate the environmental impact of traditional materials, like fiberglass, in boat construction. However, this raises concerns about biofouling and degradation, issues that have not been extensively investigated in composites, especially over a time frame representative of issues that could arise during service. Although protective solutions like biocides and specific coatings exist, degradation remains challenging when attempting to use eco-friendly natural fillers. This study specifically integrates various biological fillers, namely ceramics (mussel, oyster, clam powder) or ligno-cellulosic (i.e., Posidonia oceanica fibers) into epoxy for use in some boat components (bench seats for the bridge deck), aiming to evaluate the biofouling process under extreme (or decommissioning) conditions. In itself, epoxy does represent an ideal enclosing matrix for biomass waste, which ideally needs to be introduced in significant amounts. The development of biofouling in the specific context of Kotor’s Bay, Montenegro, for a duration of six months, and relevant composite degradation were examined. In particular, three situations were reproduced by positioning the samples in a harbor environment: (i) on the bottom of the sea (2 m. depth), (ii) immersed just below the surface (0.5 m. depth), and (iii) on the splashing surface (pier). The concerns identified appear generally limited in the case of the envisaged application, despite some significant wear effect in the case of the samples containing Posidonia. However, this study also offers information and caveats in terms of more ambitious prospective applications (e.g., the boat hull structure). Full article

Pharyngitis is a leading cause of outpatient antibiotic use, despite its typically viral or self-limiting nature. Such unnecessary antibiotic therapies are not only the cause of increasing antibiotic resistance, but also significant changes in the human microbiota in the intestines and other locations, which translate into immune disorders and an increased risk of developing several chronic diseases. Orally administered octenidine-containing lozenges provide a topical alternative; however, their effects on the host microbiota of the oral cavity, throat, and intestine remain unclear. In this study, we evaluated the antimicrobial and antibiofilm in vitro activity of octenidine lozenges against 106 microbial strains, including pathogens and commensals from the oral cavity, pharynx, and large intestine. Minimal biocidal concentrations (MBCs) and minimal biofilm eradication concentrations (MBECs) were determined under physiologically relevant exposure times: 23 min for oral contact and 24 h for intestinal transit. ADME in silico analysis confirmed the lack of absorption of octenidine through the blood–brain barrier and the gastric intestinal mucosa. At concentrations achievable in saliva and the intestinal lumen, octenidine effectively eradicated in vitro all oropharyngeal pathogens while leaving intestinal commensals unaffected. Its impact on oral commensals resembled that of routine mechanical cleaning. These in vitro findings are of high translative value because they support the use of octenidine lozenges as a safe topical treatment for pharyngeal infections, “sore throat”, without adverse effects on the gut microbiota. Full article

Biofouling is the colonization and attachment of sessile organisms on submerged surfaces, whether natural or artificial. The presence of these communities compromises the structural integrity, operational efficiency, and durability of coastal structures, resulting in high economic and environmental costs, especially when conventional removal methods involve the use of toxic biocides. In this context, this article aimed to evaluate the scientific productivity of the literature related to sustainable antifouling strategies, with an emphasis on technologically and environmentally sustainable solutions, through a bibliometric analysis. We analyzed 160 research articles and 90 patents published between 2004 and 2024. It was observed that, since 2019, there has been an increase in publications about biofouling solutions, with a notable emphasis on China’s leadership in both scientific production and patent filings. This topic has also attracted extensive international collaboration. The most promising strategies for controlling marine biofouling involve a combination of physical, chemical, and biological methods, integrated with sustainable coatings. The growing demand for low-environmental-impact solutions has driven the development of safer, more effective, and economically viable antifouling technologies. Therefore, the integration of traditional techniques with advances in biotechnology represents a strategic path to mitigating the impacts of biofouling in marine environments. Full article

As one of the key vectors for the transmission of Dengue fever, Aedes albopictus is highly ecologically adaptable. The development of environmentally compatible biological defence and control technologies has therefore become an urgent need for vector biological control worldwide. This study constructed and used double-stranded RNA (dsRNA) expression vectors targeting the cyp314a1 and cyp315a1 genes of Ae. albopictus to transform Chlamydomonas reinhardtii and Chlorella vulgaris, achieving RNA interference (RNAi)-mediated gene silencing. The efficacy of the RNAi recombinant algal strain biocide against Ae. albopictus was evaluated by administering it to Ae. albopictus larvae. The results showed that the oral administration of the cyp314a1 and cyp315a1 RNAi recombinant C. reinhardtii/C. vulgaris strains was lethal to Ae. albopictus larvae and severely affected their pupation and emergence. The recombinant algal strains triggered a burst of ROS (Reactive Oxygen Species) in the mosquitoes’ bodies, resulting in significant increases in the activities of the superoxide dismutase (SOD), peroxiredoxin (POD) and catalase (CAT), as well as significant upregulation of the mRNA levels of the CME pathway genes in larvae. In the simulated field experiment, the number of Ae. albopictus was reduced from 1000 to 0 in 16 weeks by the RNAi recombinant Chlorella, which effectively controlled the population of mosquitoes. Meanwhile, the levels of nitrogen (N), phosphorus (P), nitrate, nitrite, ammonia and COD (Chemical Oxygen Demand) in the test water decreased significantly. High-throughput sequencing analyses of 18S rDNA and 16S rDNA showed that, with the release of RNAi recombinant Chlorella into the test water, the biotic community restructuring dominated by resource competition caused by algal bloom, as well as the proliferation of anaerobic bacteria and the decline of aerobic bacteria triggered by anaerobic conditions, are the main trends in the changes in the test water. This study is an important addition to the use of RNAi recombinant microalgae as a biocide. Full article